FDA Accelerates Approval Of Amgen's Blincyto To Treat Lymphoblastic Leukemia

(RTTNews) - Amgen Inc (AMGN) said Wednesday the U.S. Food and Drug Administration has granted approval of Blincyto (blinatumomab) for the treatment of patients with Philadelphia chromosome-negative (Ph-) relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). This indication is approved under accelerated approval. Continued approval for this indication may be contingent upon verification of clinical benefit in subsequent trials.

With this approval, Blincyto becomes the first FDA-approved bispecific CD19-directed CD3 T-cell engager antibody construct product, and the first single-agent immunotherapy to be approved for the treatment of patients with Ph- relapsed or refractory B-cell precursor ALL, a rare and rapidly progressing cancer of the blood and bone marrow.

Precursor B-cell ALL is a rapidly growing type of cancer in which the bone marrow makes too many B-cell lymphoblasts, an immature type of white blood cell. The Philadelphia chromosome is an abnormality that sometimes occurs in the bone marrow cells of leukemia patients. The National Cancer Institute estimates that 6,020 Americans will be diagnosed with ALL and 1,440 will die from the disease in 2014.

Blincyto acts as a connector between a protein called CD19, which is found on the surface of most B-cell lymphoblasts, and CD3, a protein on T-cell lymphocytes. It is intended for patients whose cancer returned after treatment (relapsed) or did not respond to previous treatment (refractory).

The FDA granted Blincyto breakthrough therapy designation, priority review and orphan product designation. Blincyto is being approved more than five months ahead of the prescription drug user fee goal date of May 19, 2015, the date the agency was scheduled to complete review of the application.

The safety and effectiveness of Blincyto were evaluated in a clinical study involving 185 adults with Philadelphia chromosome-negative relapsed or refractory precursor B-cell ALL. Results showed 32 percent of participants had no evidence of disease (complete remission) for approximately 6.7 months.

The FDA is requiring Amgen to conduct a study to verify that Blincyto improves survival in participants with relapsed or refractory Philadelphia-negative precursor B-cell ALL.

Blincyto carries a boxed warning alerting patients and health care professionals that some clinical trial participants had problems with low blood pressure and difficulty breathing (cytokine release syndrome) at the start of the first treatment, experienced a short period of difficulty with thinking (encephalopathy) or other side effects in the nervous system.

The most common side effects seen in Blincyto-treated participants were fever (pyrexia), headache, swelling of tissues (peripheral edema), fever with a low number of white blood cells (febrile neutropenia), nausea, low potassium (hypokalaemia), fatigue, constipation, diarrhea and tremor.

The FDA approved Blincyto with a Risk Evaluation and Mitigation Strategy, which consists of a communication plan to inform health care providers about the serious risks and the potential for preparation and administration errors.